Background[ edit ] There are two different types of biodegradable plastic : Vegetable-based plastics, which are also loosely known as " bioplastics " or " compostable plastics ", are tested in accordance with ASTM D or EN as to their ability to biodegrade under conditions found in industrial composting or biogas facilities. The remaining chemicals are no longer plastic[ citation needed ] and are biodegradable by bacteria ,[ citation needed ] which are ubiquitous in the terrestrial and marine environments. Oxo-degradation is degradation resulting from "oxidative cleavage of macromolecules"; 2. Oxo-biodegradation is "degradation resulting from oxidative and cell-mediated phenomena, either simultaneously or successively. With regard to definition 2, an oxo-biodegredable polyolefin plastic file e.
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A number in parentheses indicates the year of last reapproval. Disposal environ-ments range from exposure in soil, landfill, and compost inwhich thermal oxidation may occur and land cover andagricultural use in which photooxidation may also occur. The conditionsshould include a range of humidity or water concentrationsbased on the application and disposal environment in mind. The measured rate of degradation at typical oxidation tempera-tures is required to compare and rank the polymers beingevaluated in that chosen application to reach a molecularweight that constitutes a demonstrable biodegradable residue using ASTM International biometer tests for CO2evolutionappropriate to the chosen environment.
Forapplications in soils, local temperatures and humidity rangesmust be considered as they vary widely with geography. It must also be established that the polymer does notundergo a phase change, such as glass transition temperature Tg within the temperature range of testing. The degree and time for biodegradation should be consistentwith ASTM International methods, and any residues from theintermediate oxidation stage and from biodegradation must beshown to be environmentally benign and not persistent Tier 3.
NOTE 1—The intended use of this guide is for comparison and rankingof data to aid in the design and development and the reduction ofenvironmental impacts of polymers that require no more than 24 monthsto oxidize and biodegrade in the intended use and disposal options andcreate no harmful or persistent residues under the appropriate disposalconditions for example, two seasons of crop-growing conditions in soil.
Note this changed all subsequent Note numbers. Current edition approved Jan. Published January Originallyapproved in Last previous edition approved in as D - United States1responsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory requirements prior to use. Referenced Documents2. Living organisms effect bioticdegradation processes and abiotic degradation processes arenonbiological in nature.
Cross-links created during oxobiodegradadationof polymers are chemical bonds created by the degradationprocess, mostly carbon-carbon bonds, and thus extremelyresistant to solvent degradation. Summary of Guide4. Subsequently, the biodegradation of these degraded polymersin diverse environments such as soil, compost, landfill, andwater may be compared and ranked using standard biometrictest methods and measuring carbon dioxide evolution.
NOTE 3—If composting is the designated disposal route, SpecificationD is the only ultimate and definitive applicable specification formeasuring biodegradation or compostability. This isshown schematically in Section 6. Each tier in this guideincludes objectives and a summary that presents test methods,method principles, test duration, and interpretation of results. Mounier 83, Box 1, Brussels, BelgiumB Accelerated testing must beperformed under conditions and temperatures that are accept-ably typical of the specific application and disposal environ-ments under consideration.
Practices D, D, andD may be used to specify the oxidative conditions andPractice D may be used to define the point of embrittle-ment. In this tier, the fragments are subjected to molecularweight analysis and a total mass balance is obtained in the process.
It must also be established that the polymerdoes not undergo a phase change, such as glass transition temperature Tg within the temperature range of testing. As an alternate degradationprocess, the test samples may be exposed to photooxidation in air as perPractices D or D and the mass change of the plastic recordedafter exposure.
If oxidation is thought to be sufficiently rapid in Tier1, suggesting that composting may be a disposal environment,then Specification D must be done and all the specifica-tions in Section 6 Detailed Requirements must be met.
Gelsare cross-linked structures arising from the free radical natureof oxidative degradation. They are insoluble in nonreactivesolvents, that is, solvents that do not break additional bonds. Normally, gels are not available to biodegradation.
Some gelsdissolve on further oxidative degradation and become availablefor ultimate biodegradation. However, the prooxidant catalyst may be excluded from the gel structure because of solubilitychanges in gel phase. In this case, the gel would become anondegradable or very slowly degradable new fraction withinthe polymer.
It is important to establish the extent of gel and itsnature or permanence in the polymer residue and report thesefindings.
The entire materialfrom the Tier 1 exposure is subjected to biodegradation testing. The percent biodegradation shall be calculated and reported asstated in the above referenced standards. The results from Tier1 and Tier 2 shall be combined and used for comparison andranking purposes between polymers of interest. Significance and Use5. Thisenables a laboratory assessment of its disposal performance in,soil, compost, landfill, and water and for use in agriculturalproducts such as mulch film without detriment to that particularenvironment.
NOTE 5—For determining biodegradation rates under compostingconditions, Specification D is to be used, including test methods andconditions as specified.
ASTM D 1. Scope 1. Disposal environments range from exposure in soil, landfill, and compost in which thermal oxidation may occur and land cover and agricultural use in which photooxidation may also occur. The conditions should include a range of humidity or water concentrations based on the application and disposal environment in mind. The measured rate of degradation at typical oxidation temperatures is required to compare and rank the polymers being evaluated in that chosen application to reach a molecular weight that constitutes a demonstrable biodegradable residue using ASTM International biometer tests for CO2 evolution appropriate to the chosen environment.
Normas e Tipos de Plásticos Biodegradáveis
More D This enables a laboratory assessment of its disposal performance in, soil, compost, landfill, and water and for use in agricultural products such as mulch film without detriment to that particular environment. However, exposure of a similar material of known outdoor performance, a control, at the same time as the test specimens allows comparison of the durability relative to that of the control under the test conditions. Scope 1. Disposal environments range from exposure in soil, landfill, and compost in which thermal oxidation may occur and land cover and agricultural use in which photooxidation may also occur. The conditions should include a range of humidity or water concentrations based on the application and disposal environment in mind. The measured rate of degradation at typical oxidation temperatures is required to compare and rank the polymers being evaluated in that chosen application to reach a molecular weight that constitutes a demonstrable biodegradable residue using ASTM International biometer tests for CO2 evolution appropriate to the chosen environment.
Standards ASTM Standards for Oxo-Biodegradable Plastics EPI supports the development of international standards relating to the establishment of practical and measurable specifications and methods for the testing of degradable and biodegradable products. Standards for Biodegradable Plastics Degradation and biodegradation requirements of plastics vary considerably with intended use including disposal compartments and EPI is working with ASTM and European standards to evaluate oxo-biodegradable claims in various environments such as landfill, soil, litter, commercial and home composting. Unfortunately, at the present time, there are no standards available for the performance of degradable and biodegradable plastics in other disposal environment other than composting. Commonly quoted standards for compostable plastics are ASTM D and EN and are related to the performance of plastics in a commercially managed compost environment and are not biodegradation standards. Both standards were developed for hydro-biodegradable polymers eg. This does not mean that they will not biodegrade; they just convert the carbon to carbon dioxide in a slightly longer time frame. Many naturally occurring materials, all biodegradable, do not convert in the time frames established by ASTM D and EN , which are explained in the Position Statement.